1. Field of the Invention
This invention relates to an attachment module used in the course of orthodontic treatment. More particularly, the present invention is directed to an attachment module for connecting bite correctors, force modules or other devices to other orthodontic components in the oral cavity.
2. Description of the Related Art
Orthodontic treatment is a specialized form of treatment within the field of dentistry, and involves movement of malpositioned teeth to orthodontically correct locations. Orthodontic treatment often greatly improves the aesthetic appearance of the patient's teeth. Orthodontic treatment can also improve the patient's occlusion, so that when the jaws are closed the upper teeth are in proper positions relative to the lower teeth.
Orthodontic treatment is often carried out by use of a system of tiny appliances, wires and other components that are commonly known collectively as “braces”. Typically, a small appliance known as a bracket is connected to each of the patient's anterior, cuspid and bicuspid teeth and an archwire placed in a slot of each bracket. The archwire forms a track to guide movement of the brackets and the associated teeth to desired positions.
End sections of orthodontic archwires are often held by appliances known as buccal tubes that are secured to the patient's molar teeth. Each buccal tube has a passage that slidably receives the end section of the archwire. Buccal tubes may be placed on the patient's first molar teeth or the patient's second molar teeth.
In orthodontic treatment, the molar teeth often serve as convenient points of anchorage for applying force to other teeth because the molar teeth are relatively large and have a plurality of roots. As a consequence, many buccal tube appliances have one or two additional passages located next to the archwire slot. The additional passages (sometimes called auxiliary tubes) can be used for connection to other orthodontic devices as desired.
For example, the orthodontic treatment of some patients includes correction of the alignment of the upper dental arch to the lower dental arch. Certain patients have a condition referred to as a Class II malocclusion wherein the lower dental arch is located an excessive distance rearward of the upper dental arch when the jaws are closed. Other patients may have an opposite condition referred to as a Class III malocclusion wherein the lower dental arch is located forward of the upper dental arch when the jaws are closed.
A number of intra-oral devices for correcting Class II and Class III malocclusions are known in the art. For example, U.S. Pat. Nos. 4,708,646, 5,352,116, 5,435,721 and 5,651,672 describe intra-oral bite correctors with flexible spring members that are connected to upper and lower arches of a patient. The length of the bite corrector is selected such that the member is curved in an arc when the patient's jaws are closed. The inherent spring bias tends to urge the members toward a normally straight orientation and provide a force that pushes one dental arch forward or rearward relative to the other dental arch when the jaws are closed.
U.S. Pat. No. 6,913,460 describes an orthodontic coupling for releasably connecting intra-oral bite correctors to buccal tubes. The coupling described in this patent includes a body with a shank that is received in a passage of the buccal tube with a flexible, snap-in retention movement. In certain embodiments described in this patent, the coupling includes rotation stops that are moved into operative positions as the shank is received in the passage. The rotation stops function to limit pivoting movement of the associated bite corrector so that the bite corrector does not contact adjacent oral tissue and cause irritation.
Relatively large intra-oral forces are often applied to orthodontic components during movement of the jaws. For example, the forces generated when chewing can be significant, especially when the patient bites into a hard food object such as hard candy, nuts or ice. The chewing forces can be especially large in molar regions of the patient's jaws, and hard food objects can transmit the forces to the attached orthodontic components. In some instances, the forces can break the components or cause the components to spontaneously detach from the teeth such that the progress of treatment is interrupted.